Table 2. Vibrational Corrected MS-CASPT2 Low-Lying Singlet Vertical Excitations (in eV) of Nitrobenzene at the Ground State C2v geometry and Comparison With Gas-Phase Experimental Results.
| state | ΔE | VCa | ΔE(Corr)b | ΔE(obs)c | refs |
|---|---|---|---|---|---|
| 1A2 | 3.83 | –0.22 | 3.61 | 3.65d | (5, 7) |
| 1B2 | 4.30 | –0.16 | 4.14 | ||
| 1B1 | 4.72 | –0.23 | 4.49 | 4.38–4.43 | (1, 7) |
| 2A1 | 5.11 | –0.17 | 4.94 | 5.11–5.00 | (1, 7) |
| 2B1 | 5.81 | –0.29 | 5.53 | ||
| 2A2 | 7.00 | –0.22 | 6.78 | ||
| 2B2 | 7.02 | –0.27 | 6.75 | ||
| 3B1 | 7.04 | –0.53 | 6.51 | 6.42 | (1, 6, 7) |
| 3A2 | 7.36 | ||||
| 3B2 | 7.51 | ||||
| 3A1 | 7.60 | 7.56 | (7) |
a
Vibrational energy correction.
b
Corrected excitation energy: ΔE(Coor) = ΔE + VC.
c
Observed absorption peaks.
d
Registered in n-hexane solution.